/*******************************************************************************
 * Copyright (c) 2000, 2008 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/

package org.eclipse.wst.jsdt.internal.ui.javaeditor;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.eclipse.core.runtime.Assert;
import org.eclipse.jface.preference.IPreferenceStore;
import org.eclipse.jface.preference.PreferenceConverter;
import org.eclipse.jface.text.BadLocationException;
import org.eclipse.jface.text.IDocument;
import org.eclipse.jface.text.IRegion;
import org.eclipse.jface.text.ITextPresentationListener;
import org.eclipse.jface.text.ITypedRegion;
import org.eclipse.jface.text.Region;
import org.eclipse.jface.text.TextUtilities;
import org.eclipse.jface.text.formatter.FormattingContextProperties;
import org.eclipse.jface.text.formatter.IFormattingContext;
import org.eclipse.jface.text.information.IInformationPresenter;
import org.eclipse.jface.text.reconciler.IReconciler;
import org.eclipse.jface.text.source.IOverviewRuler;
import org.eclipse.jface.text.source.IVerticalRuler;
import org.eclipse.jface.text.source.SourceViewerConfiguration;
import org.eclipse.jface.text.source.projection.ProjectionViewer;
import org.eclipse.jface.util.IPropertyChangeListener;
import org.eclipse.jface.util.PropertyChangeEvent;
import org.eclipse.swt.SWT;
import org.eclipse.swt.custom.BidiSegmentEvent;
import org.eclipse.swt.custom.BidiSegmentListener;
import org.eclipse.swt.custom.StyleRange;
import org.eclipse.swt.custom.StyledText;
import org.eclipse.swt.graphics.Color;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.graphics.RGB;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Display;
import org.eclipse.ui.texteditor.AbstractDecoratedTextEditorPreferenceConstants;
import org.eclipse.ui.texteditor.AbstractTextEditor;
import org.eclipse.wst.jsdt.core.JavaScriptCore;
import org.eclipse.wst.jsdt.internal.ui.text.SmartBackspaceManager;
import org.eclipse.wst.jsdt.internal.ui.text.comment.CommentFormattingContext;
import org.eclipse.wst.jsdt.ui.PreferenceConstants;
import org.eclipse.wst.jsdt.ui.text.IJavaScriptPartitions;
import org.eclipse.wst.jsdt.ui.text.JavaScriptSourceViewerConfiguration;



public class JavaSourceViewer extends ProjectionViewer implements IPropertyChangeListener {

	/**
	 * Text operation code for requesting the outline for the current input.
	 */
	public static final int SHOW_OUTLINE= 51;

	/**
	 * Text operation code for requesting the outline for the element at the current position.
	 */
	public static final int OPEN_STRUCTURE= 52;

	/**
	 * Text operation code for requesting the hierarchy for the current input.
	 */
	public static final int SHOW_HIERARCHY= 53;

	private IInformationPresenter fOutlinePresenter;
	private IInformationPresenter fStructurePresenter;
	private IInformationPresenter fHierarchyPresenter;

	/**
	 * This viewer's foreground color.
	 * 
	 */
	private Color fForegroundColor;
	/**
	 * The viewer's background color.
	 * 
	 */
	private Color fBackgroundColor;
	/**
	 * This viewer's selection foreground color.
	 * 
	 */
	private Color fSelectionForegroundColor;
	/**
	 * The viewer's selection background color.
	 * 
	 */
	private Color fSelectionBackgroundColor;
	/**
	 * The preference store.
	 *
	 * 
	 */
	private IPreferenceStore fPreferenceStore;
	/**
	 * Is this source viewer configured?
	 *
	 * 
	 */
	private boolean fIsConfigured;
	/**
	 * The backspace manager of this viewer.
	 *
	 * 
	 */
	private SmartBackspaceManager fBackspaceManager;

	/**
	 * Whether to delay setting the visual document until the projection has been computed.
	 * <p>
	 * Added for performance optimization.
	 * </p>
	 * @see #prepareDelayedProjection()
	 * 
	 */
	private boolean fIsSetVisibleDocumentDelayed= false;

	public JavaSourceViewer(Composite parent, IVerticalRuler verticalRuler, IOverviewRuler overviewRuler, boolean showAnnotationsOverview, int styles, IPreferenceStore store) {
		super(parent, verticalRuler, overviewRuler, showAnnotationsOverview, styles);
		setPreferenceStore(store);
	}

	/*
	 * @see org.eclipse.jface.text.source.SourceViewer#createFormattingContext()
	 * 
	 */
	public IFormattingContext createFormattingContext() {

		// it's ok to use instance preferences here as subclasses replace
		// with project dependent versions (see CompilationUnitEditor.AdaptedSourceViewer)
		IFormattingContext context= new CommentFormattingContext();
		Map map= new HashMap(JavaScriptCore.getOptions());
		context.setProperty(FormattingContextProperties.CONTEXT_PREFERENCES, map);

		return context;
	}

	/*
	 * @see ITextOperationTarget#doOperation(int)
	 */
	public void doOperation(int operation) {
		if (getTextWidget() == null) {
			return;
		}

		switch (operation) {
			case SHOW_OUTLINE:
				if (fOutlinePresenter != null) {
					fOutlinePresenter.showInformation();
				}
				return;
			case OPEN_STRUCTURE:
				if (fStructurePresenter != null) {
					fStructurePresenter.showInformation();
				}
				return;
			case SHOW_HIERARCHY:
				if (fHierarchyPresenter != null) {
					fHierarchyPresenter.showInformation();
				}
				return;
		}

		super.doOperation(operation);
	}

	/*
	 * @see ITextOperationTarget#canDoOperation(int)
	 */
	public boolean canDoOperation(int operation) {
		if (operation == SHOW_OUTLINE) {
			return fOutlinePresenter != null;
		}
		if (operation == OPEN_STRUCTURE) {
			return fStructurePresenter != null;
		}
		if (operation == SHOW_HIERARCHY) {
			return fHierarchyPresenter != null;
		}

		return super.canDoOperation(operation);
	}

	/*
	 * @see ISourceViewer#configure(SourceViewerConfiguration)
	 */
	public void configure(SourceViewerConfiguration configuration) {

		/*
		 * Prevent access to colors disposed in unconfigure(), see:
		 *   https://bugs.eclipse.org/bugs/show_bug.cgi?id=53641
		 *   https://bugs.eclipse.org/bugs/show_bug.cgi?id=86177
		 */
		StyledText textWidget= getTextWidget();
		if ((textWidget != null) && !textWidget.isDisposed()) {
			Color foregroundColor= textWidget.getForeground();
			if ((foregroundColor != null) && foregroundColor.isDisposed()) {
				textWidget.setForeground(null);
			}
			Color backgroundColor= textWidget.getBackground();
			if ((backgroundColor != null) && backgroundColor.isDisposed()) {
				textWidget.setBackground(null);
			}
		}

		super.configure(configuration);
		if (configuration instanceof JavaScriptSourceViewerConfiguration) {
			JavaScriptSourceViewerConfiguration javaSVCconfiguration= (JavaScriptSourceViewerConfiguration)configuration;
			fOutlinePresenter= javaSVCconfiguration.getOutlinePresenter(this, false);
			if (fOutlinePresenter != null) {
				fOutlinePresenter.install(this);
			}

			fStructurePresenter= javaSVCconfiguration.getOutlinePresenter(this, true);
			if (fStructurePresenter != null) {
				fStructurePresenter.install(this);
			}

			fHierarchyPresenter= javaSVCconfiguration.getHierarchyPresenter(this, true);
			if (fHierarchyPresenter != null) {
				fHierarchyPresenter.install(this);
			}

		}

		if (fPreferenceStore != null) {
			fPreferenceStore.addPropertyChangeListener(this);
			initializeViewerColors();
		}

		fIsConfigured= true;
	}


	protected void initializeViewerColors() {
		if (fPreferenceStore != null) {

			StyledText styledText= getTextWidget();

			// ----------- foreground color --------------------
			Color color= fPreferenceStore.getBoolean(AbstractTextEditor.PREFERENCE_COLOR_FOREGROUND_SYSTEM_DEFAULT)
			? null
			: createColor(fPreferenceStore, AbstractTextEditor.PREFERENCE_COLOR_FOREGROUND, styledText.getDisplay());
			styledText.setForeground(color);

			if (fForegroundColor != null) {
				fForegroundColor.dispose();
			}

			fForegroundColor= color;

			// ---------- background color ----------------------
			color= fPreferenceStore.getBoolean(AbstractTextEditor.PREFERENCE_COLOR_BACKGROUND_SYSTEM_DEFAULT)
			? null
			: createColor(fPreferenceStore, AbstractTextEditor.PREFERENCE_COLOR_BACKGROUND, styledText.getDisplay());
			styledText.setBackground(color);

			if (fBackgroundColor != null) {
				fBackgroundColor.dispose();
			}

			fBackgroundColor= color;

			// ----------- selection foreground color --------------------
			color= fPreferenceStore.getBoolean(AbstractDecoratedTextEditorPreferenceConstants.EDITOR_SELECTION_FOREGROUND_DEFAULT_COLOR)
				? null
				: createColor(fPreferenceStore, AbstractDecoratedTextEditorPreferenceConstants.EDITOR_SELECTION_FOREGROUND_COLOR, styledText.getDisplay());
			styledText.setSelectionForeground(color);

			if (fSelectionForegroundColor != null) {
				fSelectionForegroundColor.dispose();
			}

			fSelectionForegroundColor= color;

			// ---------- selection background color ----------------------
			color= fPreferenceStore.getBoolean(AbstractDecoratedTextEditorPreferenceConstants.EDITOR_SELECTION_BACKGROUND_DEFAULT_COLOR)
				? null
				: createColor(fPreferenceStore, AbstractDecoratedTextEditorPreferenceConstants.EDITOR_SELECTION_BACKGROUND_COLOR, styledText.getDisplay());
			styledText.setSelectionBackground(color);

			if (fSelectionBackgroundColor != null) {
				fSelectionBackgroundColor.dispose();
			}

			fSelectionBackgroundColor= color;
		}
    }

    /**
     * Creates a color from the information stored in the given preference store.
     * Returns <code>null</code> if there is no such information available.
     *
     * @param store the store to read from
     * @param key the key used for the lookup in the preference store
     * @param display the display used create the color
     * @return the created color according to the specification in the preference store
     * 
     */
    private Color createColor(IPreferenceStore store, String key, Display display) {

        RGB rgb= null;

        if (store.contains(key)) {

            if (store.isDefault(key)) {
				rgb= PreferenceConverter.getDefaultColor(store, key);
			} else {
				rgb= PreferenceConverter.getColor(store, key);
			}

            if (rgb != null) {
				return new Color(display, rgb);
			}
        }

        return null;
    }

	/*
	 * @see org.eclipse.jface.text.source.ISourceViewerExtension2#unconfigure()
	 * 
	 */
	public void unconfigure() {
		if (fOutlinePresenter != null) {
			fOutlinePresenter.uninstall();
			fOutlinePresenter= null;
		}
		if (fStructurePresenter != null) {
			fStructurePresenter.uninstall();
			fStructurePresenter= null;
		}
		if (fHierarchyPresenter != null) {
			fHierarchyPresenter.uninstall();
			fHierarchyPresenter= null;
		}
		if (fForegroundColor != null) {
			fForegroundColor.dispose();
			fForegroundColor= null;
		}
		if (fBackgroundColor != null) {
			fBackgroundColor.dispose();
			fBackgroundColor= null;
		}

		if (fPreferenceStore != null) {
			fPreferenceStore.removePropertyChangeListener(this);
		}

		super.unconfigure();

		fIsConfigured= false;
	}

	/*
	 * @see org.eclipse.jface.text.source.SourceViewer#rememberSelection()
	 */
	public Point rememberSelection() {
		return super.rememberSelection();
	}

	/*
	 * @see org.eclipse.jface.text.source.SourceViewer#restoreSelection()
	 */
	public void restoreSelection() {
		super.restoreSelection();
	}

	/*
	 * @see org.eclipse.jface.util.IPropertyChangeListener#propertyChange(org.eclipse.jface.util.PropertyChangeEvent)
	 */
	public void propertyChange(PropertyChangeEvent event) {
		String property = event.getProperty();
		if (AbstractTextEditor.PREFERENCE_COLOR_FOREGROUND.equals(property)
				|| AbstractTextEditor.PREFERENCE_COLOR_FOREGROUND_SYSTEM_DEFAULT.equals(property)
				|| AbstractTextEditor.PREFERENCE_COLOR_BACKGROUND.equals(property)
				|| AbstractTextEditor.PREFERENCE_COLOR_BACKGROUND_SYSTEM_DEFAULT.equals(property)
				|| AbstractDecoratedTextEditorPreferenceConstants.EDITOR_SELECTION_FOREGROUND_COLOR.equals(property)
				|| AbstractDecoratedTextEditorPreferenceConstants.EDITOR_SELECTION_FOREGROUND_DEFAULT_COLOR.equals(property)
				|| AbstractDecoratedTextEditorPreferenceConstants.EDITOR_SELECTION_BACKGROUND_COLOR.equals(property)
				|| AbstractDecoratedTextEditorPreferenceConstants.EDITOR_SELECTION_BACKGROUND_DEFAULT_COLOR.equals(property))
		{
			initializeViewerColors();
		}
	}

	/**
	 * Sets the preference store on this viewer.
	 *
	 * @param store the preference store
	 *
	 * 
	 */
	public void setPreferenceStore(IPreferenceStore store) {
		if (fIsConfigured && (fPreferenceStore != null)) {
			fPreferenceStore.removePropertyChangeListener(this);
		}

		fPreferenceStore= store;

		if (fIsConfigured && (fPreferenceStore != null)) {
			fPreferenceStore.addPropertyChangeListener(this);
			initializeViewerColors();
		}
	}
	
	/*
	 * @see org.eclipse.jface.text.ITextViewer#resetVisibleRegion()
	 * 
	 */
	public void resetVisibleRegion() {
		super.resetVisibleRegion();
		// re-enable folding if ProjectionViewer failed to due so
		if ((fPreferenceStore != null) && fPreferenceStore.getBoolean(PreferenceConstants.EDITOR_FOLDING_ENABLED) && !isProjectionMode()) {
			enableProjection();
		}
	}

	/*
	 * @see org.eclipse.jface.text.source.SourceViewer#createControl(org.eclipse.swt.widgets.Composite, int)
	 */
	protected void createControl(Composite parent, int styles) {

		// Use LEFT_TO_RIGHT unless otherwise specified.
		if (((styles & SWT.RIGHT_TO_LEFT) == 0) && ((styles & SWT.LEFT_TO_RIGHT) == 0)) {
			styles |= SWT.LEFT_TO_RIGHT;
		}
			
		super.createControl(parent, styles);

		fBackspaceManager= new SmartBackspaceManager();
		fBackspaceManager.install(this);

		StyledText text= getTextWidget();
		text.addBidiSegmentListener(new  BidiSegmentListener() {
			public void lineGetSegments(BidiSegmentEvent event) {
				if (redraws()) {
					event.segments= getBidiLineSegments(event.lineOffset, event.lineText);
				}
			}
		});
	}

	/**
	 * Returns the backspace manager for this viewer.
	 *
	 * @return the backspace manager for this viewer, or <code>null</code> if
	 *         there is none
	 * 
	 */
	public SmartBackspaceManager getBackspaceManager() {
		return fBackspaceManager;
	}

	/*
	 * @see org.eclipse.jface.text.source.SourceViewer#handleDispose()
	 */
	protected void handleDispose() {
		if (fBackspaceManager != null) {
			fBackspaceManager.uninstall();
			fBackspaceManager= null;
		}

		super.handleDispose();
	}

	/**
	 * Prepends the text presentation listener at the beginning of the viewer's
	 * list of text presentation listeners.  If the listener is already registered
	 * with the viewer this call moves the listener to the beginning of
	 * the list.
	 *
	 * @param listener the text presentation listener
	 * 
	 */
	public void prependTextPresentationListener(ITextPresentationListener listener) {

		Assert.isNotNull(listener);

		if (fTextPresentationListeners == null) {
			fTextPresentationListeners= new ArrayList();
		}

		fTextPresentationListeners.remove(listener);
		fTextPresentationListeners.add(0, listener);
	}

	/**
	 * Sets the given reconciler.
	 *
	 * @param reconciler the reconciler
	 * 
	 */
	void setReconciler(IReconciler reconciler) {
		fReconciler= reconciler;
	}

	/**
	 * Returns the reconciler.
	 *
	 * @return the reconciler or <code>null</code> if not set
	 * 
	 */
	IReconciler getReconciler() {
		return fReconciler;
	}

	/**
	 * Returns a segmentation of the given line appropriate for BIDI rendering. The default
	 * implementation returns only the string literals of a java code line as segments.
	 *
	 * @param widgetLineOffset the offset of the line
	 * @param line the content of the line
	 * @return the line's BIDI segmentation
	 */
	protected int[] getBidiLineSegments(int widgetLineOffset, String line) {
		if ((line != null) && (line.length() > 0)) {
			int lineOffset= widgetOffset2ModelOffset(widgetLineOffset);
			try {
				return getBidiLineSegments(getDocument(), lineOffset);
			} catch (BadLocationException x) {
				return null; // don't segment line in this case
			}
		}
		return null;
	}

	/**
	 * Returns a segmentation of the line of the given document appropriate for
	 * BIDI rendering. The default implementation returns only the string literals of a java code
	 * line as segments.
	 *
	 * @param document the document
	 * @param lineOffset the offset of the line
	 * @return the line's BIDI segmentation
	 * @throws BadLocationException in case lineOffset is not valid in document
	 */
	protected static int[] getBidiLineSegments(IDocument document, int lineOffset) throws BadLocationException {

		if (document == null) {
			return null;
		}

		IRegion line= document.getLineInformationOfOffset(lineOffset);
		ITypedRegion[] linePartitioning= TextUtilities.computePartitioning(document, IJavaScriptPartitions.JAVA_PARTITIONING, lineOffset, line.getLength(), false);

		List segmentation= new ArrayList();
		for (int i= 0; i < linePartitioning.length; i++) {
			if (IJavaScriptPartitions.JAVA_STRING.equals(linePartitioning[i].getType())) {
				segmentation.add(linePartitioning[i]);
			}
		}


		if (segmentation.size() == 0) {
			return null;
		}

		int size= segmentation.size();
		int[] segments= new int[(size * 2) + 1];

		int j= 0;
		for (int i= 0; i < size; i++) {
			ITypedRegion segment= (ITypedRegion) segmentation.get(i);

			if (i == 0) {
				segments[j++]= 0;
			}

			int offset= segment.getOffset() - lineOffset;
			if (offset > segments[j - 1]) {
				segments[j++]= offset;
			}

			if ((offset + segment.getLength()) >= line.getLength()) {
				break;
			}

			segments[j++]= offset + segment.getLength();
		}

		if (j < segments.length) {
			int[] result= new int[j];
			System.arraycopy(segments, 0, result, 0, j);
			segments= result;
		}

		return segments;
	}

	/**
	 * Delays setting the visual document until after the projection has been computed.
	 * This method must only be called before the document is set on the viewer.
	 * <p>
	 * This is a performance optimization to reduce the computation of
	 * the text presentation triggered by <code>setVisibleDocument(IDocument)</code>.
	 * </p>
	 * 
	 * @see #setVisibleDocument(IDocument)
	 * 
	 */
	void prepareDelayedProjection() {
		Assert.isTrue(!fIsSetVisibleDocumentDelayed);
		fIsSetVisibleDocumentDelayed= true;
	}
	
	/**
	 * {@inheritDoc}
	 * <p>
	 * This is a performance optimization to reduce the computation of
	 * the text presentation triggered by {@link #setVisibleDocument(IDocument)}
	 * </p>
	 * @see #prepareDelayedProjection()
	 * 
	 */
	protected void setVisibleDocument(IDocument document) {
		if (fIsSetVisibleDocumentDelayed) {
			fIsSetVisibleDocumentDelayed= false;
			IDocument previous= getVisibleDocument();
			enableProjection(); // will set the visible document if anything is folded
			IDocument current= getVisibleDocument();
			// if the visible document was not replaced, continue as usual
			if ((current != null) && (current != previous)) {
				return;
			}
		}
		
		super.setVisibleDocument(document);
	}

	/**
	 * {@inheritDoc}
	 * <p>
	 * Performance optimization: since we know at this place
	 * that none of the clients expects the given range to be
	 * untouched we reuse the given range as return value.
	 * </p>
	 */
	protected StyleRange modelStyleRange2WidgetStyleRange(StyleRange range) {
		IRegion region= modelRange2WidgetRange(new Region(range.start, range.length));
		if (region != null) {
			// don't clone the style range, but simply reuse it.
			range.start= region.getOffset();
			range.length= region.getLength();
			return range;
		}
		return null;
	}
}
